Add private API to notify end of initialization.

chrome/common/extensions/api/_permission_features.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 {
   "activeTab": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"],
     "min_manifest_version": 2
   },
@@ skipping 244 matching lines @@
     "inplies_full_url_access": true
   },
   "inputMethodPrivate": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app", "platform_app"],
     "whitelist": [
       "haiffjcadagjlijoggckpgfnoeiflnem",  // Citrix Receiver
       "gnedhmakppccajfpfiihfcdlnpgomkcf",  // Citrix Receiver Beta
       "fjcibdnjlbfnbfdjneajpipnlcppleek",  // Citrix Receiver Dev
       "pnhechapfaindjhompbnflcldabbghjo",  // HTerm
-      "okddffdblfhhnmhodogpojmfkjmhinfp"   // HTerm dev
+      "okddffdblfhhnmhodogpojmfkjmhinfp",  // HTerm dev
+      "fpfbhcjppmaeaijcidgiibchfbnhbelj"  // Google Japanese Input
     ]
   },
   "location": [
     {
       "channel": "dev",
       "extension_types": [
         "extension", "packaged_app", "hosted_app", "platform_app"
       ]
     },
     {
@@ skipping 299 matching lines @@
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   }
 }